Electric valve translating circuit



ELECTRIC VALVE TRANSLATING CIRCUIT Original Filed Feb. 29, 1935 2 Sheets-Sheet 1 Inventor: Ern st F W. Alexanderson,

i Attorney.

Sept. 7, 1937. E. F. w. ALEXANDERSON 2,092,545

ELECTRIC VALVE TRANSLATING CIRCUIT Original Filed Feb. 29, 1935 2 Sheets-Sheet 2 In ventor: Ern st F. W Alexande r-son His ttorney.

PM 1 m1 2 2 5 ErnstF.W.AIexander-|m,8cheneetady,N.Y..

Issignor to General Electric Company, a cornotation of New York Original application. February 86,433. Divided and be: 21, 1938, Serial N 9Claims.

29, 1936, BerialNo. this alIplicaflon'Novem- 112,041

(Cl. I'll- 281) My invention relates to electric valve translating circuits and more particularly to control circults for electric valve translating apparatus.

This application is a division of my application Serial No. 66,433, filed February 29, 1936, entitled Electric valve translating circuits, and assigned to the assignee of the present application.

Heretofore there have been devised many arrangements for controlling the energization of electric valve apparatus in accordance with a combination or electrical conditions. For example, in electric valve frequency changing systems the auxiliary control apparatus has been cumbersome and complicated. In many electric valve translating systems employing electric valves to obtain a frequency transformation, the conductivity of the valves has been controlled by mechanical means such as commutators or distributors acting in conjunction with electrical control means. While these systems have proved satisfactory in many applications, there has been evidenced a decided need for control apparatus entirely electrical in nature for controlling the conductivity of electric valve means in accordance with a number or combination of electrical conditions.

It is an object of my invention to provide a new and improvedelectric valve translating circuit.

It is another object of my invention to provide new and improved electric valve control circuits for controlling electric valve translating circuits.

It is'a further object of my invention to provide improved circuits for controlling electric valve frequency changing circuits.

In accordance with the illustrated embodiments of my invention, I provide electric valve converting systems controlled by excitation circuits entirely electrical in nature and in operation for controlling the conductivity of associated electric valve means in accordance with a number of different predetermined electrical conditions. In accordance with one feature of my invention, I employ a control electronic discharge device having at least two control members or electrodes for controlling the conductivity of the main power'electric valve means in accordance with a combination of electrical conditions. Ihe control members of the electronicdischarge devices are energized in accordance with at least two separate electrical conditions of an associated circuit, or circuits, to control the conductivity of the control discharge device and hence to effect control of the conductivity of the main electric valve means. The control electronic discharge device is so constructed and arranged that the control members act conjointly to eilect control of the conductivity of the discharge device. lhat is, the discharge device remains noconductive until voltages of predetermined minimum values are impressed upon the respective control members. The control discharge device may be maintained non-conductive by impressing a suitable negative potential upon either 01 the control members.

In accordance with another embodiment of my invention, instead of employing a plurality of control members in a single valve, I provide an excitation circuit comprising two serially-connected electronic discharge devices each having a single control member for effecting control of the conductivity 01' an electric valve of the gaseous type having an immersion-ignitor control member. The excitation circuit comprising the serially-connected electronic devices is energized in response to the voltage appearing across the anode and the cathode of the main electric valve. Each of the serially-connected electronic discharge devices is energized in response to predetermined diilerent electrical conditions of the same or difierent circuits. When the predetermined electrical conditions are satisfied both electronic discharge devices are rendered conductive to eii'ect energimtion of the control circuit for the main electric valve. So long as these electrical conditions are met, the excitation circuit will impress periodically suitable potentials upon the control member of the main electric valve and conversely when either, or both, of the predetermined electrical conditions depart from a predetermined range, or change in'character, one or both of the control devices will be rendered non-conductive to interrupt the control circuit for the main electric valve.

In accordance with a further embodiment oi. my invention, I provide an improved excitation circuit entirely electrical in nature and operation for controlling the conductivity of electric valve translating apparatus for transmitting energy between alternating current circuits of the same or dlfl'erent frequencies. The excitation circuit may comprise a plurality of electronic discharge devices, each having a single control member, or it may comprise a single electronic discharge device having a plurality 01' control members. -'I'he conductivity oi the control electronic device, and hence the conductivity of the main associated electric valve means, is controlled in accordance with the voltages and hence the frequencies 01' the respective alternating current circuits which the electric valve translating circuit interconnects. By means of selective .energization of the phase windings of the interconnecting translating apparatus, I provide an improved system for establishing electrical rotating fields for either stationary or rotary electrical apparatus.

For a better understanding of my invention, reference may be had to the following description taken in connection with the accompanying drawings and its scope 'will be pointed out in the appended claims.

Fig. 1 of the drawings, diagrammatically represents an embodiment of my invention as applied to an electric valve translating circuit employing two main power electric valves. An excitation circuit is provided for each of the main electric valves and comprises an electronic discharge device having at least two control members for controlling the conductivity of the main 0 power electric valve in accordance with two electrical conditions. Fig. 2 diagrammatically shows a modification oi the embodiment of my invention illustrated in Fig. 1 as applied to a similar electric valve translating system in which the excitation circuit comprising two serially connected electronic devices for each of the main power electric valves is energized in response to the voltageappearing across the anode and the cathode of the associated main electric valve, and

' Fig. 3 shows a further embodiment of my invention as applied to an electric valve translating circuit for transmitting energy between an alternating current circuit of constant frequency and an alternating current of variable frequency such as a dynamo-electric machine of-the synchronous type.

Referring now to Fig. 1 of the accompanying drawings, my invention is diagrammatically illustrated as applied to electric valve converting apparatus for transmitting energy between a three phase alternating current circuit and a single phase alternating current circuit. For the purpose of explaining and illustrating my invention, I have shown electric valves I and 2 L5 of the gaseous type having anodes 3 and 4, mercury pool cathodes 5 and 6 and immersionignitor control members I and 9 for interconnecting a polyphase alternating current supply circuit 9 and a single phase alternating current load circuit III through a transformer II having a primary winding I2 and a, secondary winding I3. The main power electric valves I and 2 are oppositely disposed or connected. That is, the cathode 5 oi. electric valve I is connected to the anode 4 oi electric valve 3 through a conductor II, and the anode 3 of electric valve l and the cathode of electric valve 2 are connected to the same conductor of the polyphase supply circuit 9 through conductors I5 and I6, respectively. The cathode 5 of electric valve I and the anode 4 of electric valve 2 are connected to one side of the secondary winding I3 of transformer II through a conductor I'I, while the other terminal of the secondary winding I3 is connected to the supply circuit 9 through a conductor I8.

To provide means for controlling the conductivity of electric valves I and 2 in accordance with electrical conditions of the supply circuit 9 and the load circuit Ill, I employ excitation circuits I9 and 20, respectively. The excitation circuits I9 and 20 are energized from the supply circuit 9 by a transformer 2I having primary windings 22 and secondary windings 23 and 24 through any conventional phase shifting device, such as the rotary phase shifting arrangement 26. Each of the excitation circuits I9 and 29 is energized from a suitable secondary winding of the transformer 2|. For example, the excitation circuit I9 for electric valve I comprises the secondary winding 23 of transformer 2I for controlling the conductivity of the main electric valve I in response to an electrical condition of the supply circuit 9. A transformer 26,

. which may be of the type to supply a voltage of peaked wave form, having a primary. winding 21 and a. secondary winding 28, is employed to control the conductivity of electric valve I through an electronic discharge device 29, prefe'i'ably oi' the gaseous type, in response to an electrical condition of the load circuit III. By the term electronic discharge device of the gaseous type I intend t'oinclude electric valves employing any ionizable medium such as a gas or vapor. The electronic discharge device 29 is provided with an anode 30, a cathode 3I and control members 32 and 33 and is employed to. correlate the predetermined electrical conditions of the supply circuit 9 and the load circuit III to effect the desired periodic energization of electric valve I through the control member I. The control members 32 and 33 of electronic discharge device 29 co-operate to control the conductivity of the device 29 and when suitable voltages above predetermined minimum voltages are impressed upon the respective control members, the device 29 is rendered conductive. However, either or both of the control members 32 and 33 may maintain the electronic discharge device 29 non-conductive if a voltage below a predetermined minimum value is impressed upon either of the control members.

To obtain a voltage of suitable magnitude and wave form for controlling the conductivity of the main electric valves I and 2, I employ circuits 34 in the excitation circuits I9 and 20, respectively,

for impressing upon the immersion-ignitor control members I and 8 voltages in accordance with the desired sequence of operation. The circuits 34 each comprises a capacitance 35 which is periodically charged from the secondary winding 23 through a resistance 39 and a conductor 31 connected to an electrical neutral 38 of secondary winding 23. To impress upon the control member 32 of electronic discharge device 29 a potential of suitable magnitude and phase relation relative to the voltage of the supply circuit 9, I use phase shifting circuit connected between the lower terminal of the secondary winding 23 and the neutral connection 38 comprising a capacitance 39 and resistance 40. A resistance 4| is connected in series with this phase shifting circuit and the control member 32 of electronic discharge device 29. The common connection between capacitance 35 and resistance 40 is connected to the cathode 3| of electronic discharge device 29 by a conductor 42. One terminal or the excitation circuit I9 for the electric valve I is connected to the immersion-ignitor control member I of electric valve I through a conductor 43, and the other terminal of the excitation circuit I9 is connected to the cathode 5 of electric valve I through a conductor ll, anode 30 and cathode 3I of electronic discharge device 29 and conductor 42. The right-hand terminal of the second ary winding 28 of transformer 26 is connected to the cathode 3| of electronic discharge device 29 and the left-hand terminal of secondary winding 28 is connected to the control member 33 through a current limiting resistor 45.

In explaining the operation of the embodiment pI-s of my invention diagrammatically shown in Fig.

1, let it be assumed that the alternating current a supply circuit 9 is of a higher frequency than the alternating current load circuit i9 and that current is being transferred between these two circuits by the interconnected electric valve means I and 2. Under the assumed conditions, the electric valve I should be rendered conductive, for example, during positive half cycles of the alternating potential of the supply circuit 9 and concurrently during an interval corresponding to a positivehalf cycle of the potential of the load circuit ii. In other words, the electric valves i and 2 will be conductive alternately during alternate half cycles of a relatively higher frequency of the supply circuit 9. During a half cycle of predetermined sign or the potential of the lower frequency circuit I II, electric valves i and 2 will alternately conduct current in response to the higher frequency potential of the supply circuit 9 to supply current to the secondary winding l3 of transformer ll. Each of the electric valves i and 2 will be rendered conductive intermittently to elect transfer of current from the supply circuit 9 to the load circuit ill during half cycles of predetermined sign of the lower frequency potential of alternating current circuit II. For example, the excitation circuit l9 will operate to impress voltage of Suitable wave form upon the control member I of electric valve I in predetermined phase relation with the voltage of the alternating current circuit 9. The capacitance 35 of the circuit 34 will be charged during positive half cycles of alternating potential of circuit 9 by means of the secondary winding 23 of transformer 2|. When the electronic discharge device 29 is rendered conductive in response to suitable potentials being impressed upon the control members 32 and 33, the capacitance 35 will discharge through the circuit comprising conductor 43, control member 1 of electric valve I, conductor 44, electronic device" 29, conductor 42, and the capacitance 35. The electronic discharge device 29 will be rendered conductive-only during those intervals in which predetermined electrical conditions of the alternating current circuit 9 and the alternating current circuit iii are satisfied. In this manner, the capacitance 35 will be charged during positive half cycles of the relatively higher frequency of the alternating current circuit 9 and will be discharged during the following half cycles of potential. The polarities of the potentials impressed on the control members 32 and 33 of electronic discharge device 29 by the phase shifting circuit comprising capacitance 39 and resistance 40 and the secondary winding 23 of transformer 26, respectively, determines the instant at which the device 29 is rendered conductive. Since the control members 32 and 33 of device 29 must act 'conjointly to render the device 29 conductive, the electric valve i will be rendered conductive at only those intervals dur ing which it is desired to transmit current from the alternating current circuit 9 to the alternating current circuit iii.

It should be understood that the rotary phase shifting arrangement 25 may be employed to retard the phase of the control potential impressed upon control member I by excitation circuit i 9 relative to the potential impressed on the anode 3 of electric valve i. While for the purpose of explaining my invention I have shown two electric valves interconnecting alternating current circuits, it should be understood that my invention in its broader aspects may be applied to and 2 of the gaseous .type employing an immersion-ignitor control member, is employed for transmitting energy between alternating current supply circuit 9 and alternating current load circuit i0. To control the conductivity of the electric valves l and 2 during predetermined intervals, I employ excitation circuits 49 and 41, respectively. Each of the excitation circuits 46 and 41 is energized in accordance with the voltage appearing across the anode and cathode of the respective main power electric valves i and 2 and in accordance with predetermined electrical conditions of the supply circuit 9 and the load circuit Iii and each comprises two serially-connected electronic devices 49 and 49, preferably of the gaseous or vapor type, having anodes 59 and 5|, cathodes 52 and 53 and control members 54 and 55, respectively.

The conductivity of the electronic device 43 is controlled in accordance with an electrical condition, such as the voltage, of the load circuit l3 through a transformer 56 having a primary winding 51 and a secondary winding 58, and the conductivity of the electronic device 49 is controlled in accordance with an electrical condition, such as the voltage, of supply circuit 9 through a transformer 59 having a primary winding 60 and a secondary winding 6|. The transformer 59 is energized from the supply circuit 9 through the rotary phase shifter 25, secondary winding 23 of transformer 2i, conductors 62 and 63 and unidirectional conducting device 64. A transformer 65 having secondary windings 66 and 61 is energized from any suitable auxiliary source of alternating potential to energize the cathodes 52 and 53 of electronic devices 43 and 49, through conductors 66 and 69, respectively. A potential which varies in accordance with an electrical condition of the load circuit I0 is impressed across the control member 54 and cathode 52 of elec tronic device 48 by secondary winding 58 of transformer 56, through a conductor 10, a suitable negative voltage biasing means such as a battery H, and a current limiting resistance 12, conductors 68 and a conductor 13. A potential, which varies in accordance with an electrical condition of the supply circuit 9, is impressed across the control member 55 and cathode 53 of electronic device 49 by the secondary winding ii of transformer 59, through a conductor 14 which is connected to the right-hand terminal of winding 6|, a current limiting resistance 15, and a conductor 16 which connects the cathode 53 to the left-hand terminal of the secondary winding 6| of transformer. 59. The left-hand terminal of the secondary winding 6i of transformer 59 is also connected to the control member I of electric valve i by a conductor 17. The anode 59 of electronic device 43 is connected to the anode 3 of electric valve 1 through a resistance I9 and any conventional current limiting device, such as a fuse I9.

As explained in connection with the operation of the embodiment of my invention diagrammatically shown in Fig. 1, the embodiment of my invention represented in Fig. 2 may be best explained by considering the operation of the system when the frequency of the supply circuit 9 is greater than the frequency of the load circuit I8. To obtain the desired periodic energization of the electric valves I and 2, and hence to control the conductivityrof the valves I and 2 at predetermined times relative to the polarities of the potentials of circuits 9 and I8, the electronic discharge devices 48 ancL49 in each of the excitation circuits 46 and 41 act conjointly to effect energization at these predetermined intervals. Since the conductivity of the electronic device 49 is controlled in accordance with an electrical condition of the supply circuit 9 and since the conductivity of the electronic device 48 is controlled in accordance with an electrical condition of the load circuit I8, to obtain energization of the electric valve I and hence to render the associated valve conductive, the electronic devices 48 and 49 must both be conductive during predetermined intervals, or, in other words, these devices must be conductive concurrently to efiect energization of the immersion-ignitor 1 by utilizing the potential appearing between anode 3 and cathode 5 of valve I. During those intervals in which these predetermined conditions are satisfied, electronic devices 48 and 49 will be rendered conductive to effect energization of the immersion-ignitor 1 through a circuit comprising fuse 19, current limiting resistor 18, electronic, device 48, electronic device 49, conductor 16 and conductor 11.

It should be understood that while I have described in detail the operationof the excitation circuit 46, the excitation circuit 41 operates in a similar manner to control the conductivity of electric valve 2 during alternate half cycles of the high frequency potential of the alternating current supply circuit 9. Furthermore, it should be understood that I may e'mploy a group of valves similarly disposed in regard to the other phases of the alternating current supply circuit 9 to effect energy transfer between polyphase alternating current circuits.

Referring now to Fig. 3 of the accompanying drawings, a further embodiment of my invention is diagrammatically illustrated as applied to an electric valve translating system for transmitting energy between an alternating current circuit 88 and a dynamo-electric machine 8| of the synchronous type by means of any suitable electric valve aggregate such as the electric valves 82 to 81, inclusive, of the gaseous type having immersion-ignitor control. members \88. The dynamoelectric machine 8| is provided with a plurality of inductive phase windings 89, 98, and 9|, an electrical neutral 92, a rotating member 93 and an inductive field winding 94. The electric valves 82-81, inclusive, are energized from the alternating current supply circuit 88 through a transformer 5 having a secondary winding 96 and an electri 1 neutral 91. Electric valves 82 and 85,

83 and 86, and 84 and 81 serve to energize phase windings 89, 98, and 9|, respectively, of machine 8| in a predetermined sequence to establish a rotary field in the machine and to effect thereby rotation of the member 93. The unidirectional current which these groups of valves supply to the respective phase windings is returned. from the electrical neutral 92 through the field winding 94 to the electrical neutral 91 of transformer 95 through a conductor 98. To control the contronic discharge devices I -H8, respectively,

preferably of the gaseous type, each having an anode III, a cathode H2 and control members H3 and H4. Each of these excitation circuits is also arranged similar to the excitation circuits I9 and 28 described in connection with the embodiment of my invention diagrammatically shown in Fig. 1. The excitation circuits 99-I84 may be energized from the supply circuit 88 through any suitable phase shifting arrangement such as the rotary phase shifter I I5.

To provide means for controlling the conductivity of the electric valves 82 to 81 in accordance with an operating condition, such as the speed of the dynamo-electric machine 8|, a distributor mechanism H6 is employed. This distributor may be of the electrical or mechanical type and as shown is of the mechanical type comprising a rotary conducting segment H1 which establishes contact successively with brushes H8, H9, and I28 to effect energization of the proper excitation circuit at a predetermined time relative to the speed and position of the rotating member 93. For example, the brush I I8 connects excitation circuits IM and I84 to the output of the-phase shifter H5 through conductors I2I and I22 and undirectional conducting devices I23 and I24. Since the potentials impressed between the anodes of electric valves 84 and 81 are opposite in phase, that. is 188 electrical degrees out of phase, it is desirable to efiect energization of the associated excitation circuits I8I and I84 only during half cycles of predetermined sign. Since the unidirectional conducting devices I23 and I24 are oppositely disposed, the excitation circuits IM and I84 are energized during half cycles of opposite polarity of the alternating potential supplied by the phase shifter H5. Similarly, brush H9 is connected to excitation circuits 99 and I82 In addition to the above mentioned means for controlling the conductivity of the electric valves 82-81 in accordance with an operating condition of the dynamo-electric machine 8|, I employ a transformer I21 having primary windings I28 energized in accordance with the voltage of phase windings 89-9I, and secondary windings I29-I34, inclusive. Secondary windings I29 and I38 of transformer I21 are connected to control members H3 of the electronic devices I 81 and I I8, respectively, through conductors I35 and I36 to control the energization of control members H3 and hence to control the conductivity of these valves in accordance with an electrical condition of the associated phase winding 9| of machine 8|. Similarly, secondary windings I3I, I32 and I33, I34 are associated with electronic devices I86, I89 and I85, I88, respectively, through conductors I31-I 48, respectively.

A switch 'I4I having stationary contacts I42 and I43 and a movable contact I 44 may be em- Theoperation oftheembodimentl gnsiyin-- vention diagrammatically shownin may be best explained by considering the operation of the electric translating apparatus when the supplycircuitflisenergisedfromasourceof suitable frequency, such as an ordinary commercial frequency, and the dynamo-electric machine I is not rotating. Let it be further assumed that contact I of switch ill engagm contact I99 and that the phase of the alternating voltages impressed p n the immersion-ignitor control member 99 of electric valves 92-91 is sufllciently retarded in phase relative to the voltage impressed upon the associated anodes so that the average'voltage, andhence the average current. which these valves supply is relatively small and insumcient to cause rotation of the member 99. Under the assumed conditions, the distributor H9 is in a position so that the conducting segment III is in contact with brush H9 to effect ener- .gization of excitation circuits "I and I99. Unidirectional current will, therefore, be supplied to phase winding 9i through electric valves 99 and 91, suitable excitation currents for these valves being supplied by excitation circuits I" and I94 through electronic discharge devices I91 and H9. If the phase of the excitation current supplied by the excitation circuits IN. and I99 be advanced by means of phase shifter 9, the average voltage, and hence the average current, furnished by electric valves 94 and 91 will be increased and since the'rotating member 99 of machine 9| is in a torque producing position relative to the phase winding 9i, the member 93 will be caused to accelerate at a rate dependent upon the connected load. Assuming that the interactions of the magnetomotive forces of the phase winding 9i and field winding." of machine 9i are in the proper directions so that the member 99 rotates in a clockwise direction, the conducting segment.

ill of distributor H6 will establish contact with brush H9 to eifect energization of excitation circuits 99 and I92, which in turn will render electric valves 92 and 95 conductive to supply unidirectional current to the phase winding 99. In this manner, it will be understood that the distributor H9 efiects energization of the proper excitation circuits to render electric valves 92-91 conductive in predetermined sequence to establish the desired periodic energization of the phase windings 99-9l when the rotating member 99 is in a torque producing position relative to the respective phase windings. It should also be noted that the distributor 9 effects transfer or commutation of unidirectional current between the phase windings 99-9i, thereby producing the necessary rotating field.

The excitation circuits 99-499 operate to furnish a voltage of suitable magnitude and wave form to the control members 99 of electric valves 92-91 in the proper sequence to render these valves conductive in accordance with the voltage of the supply circuit 99 and in accordance with an operating condition of the dynamo-electric machine 9|.

If it is desired to control the conductivity of the electric valves 92-91 by means entirely electrical in nature and operation, the movable member I of switch Ill may be placed in contact with stationary members I92 to render the distributor H9 ineffective. Since the transformer I2! is energized in accordance with the voltage 0,000,045 8 ployed torender the distributor ii9 ineiiecti'e y of the phase windings 99-", the conductivity of ,shortcircuitingthebmshes ill-I29. theelectrcnic devices ill to iilwiilbecontrolled in accordance with an operating condition of the machine 9i andwill also be controlledin accordance with thevoltage of the supply circuit 99. The electronic devices l99-i i9, through the control members H9 and I, simply current to the immersion-ignitor control members 94 of electric valves 92-91 only during those intervals in which these two conditions are satisfied.

Although in Fig. 3 of the accompanying drawings I have shown my invention as applied to an electric valve translating circuit for transmitting energy between a single phase alternating current circuit and a variable frequency load cirit should beunderstood that my invention in its broader aspects valve translating circuits generally for transmitting energy between alternating and direct current circuits or between alternating current circuits of variable frequency.

My copending patent application Serial No. 66,432, filed February 29, 1936, describes an electric valve translating system employing an electric ance with two independent this application is assigned to the assignee of the present application. The electric valve circuits shown in Figs. 1, 2, and 3 are disclosed and claimed in my copending application Serial No. 66,433, filed February 29, 1936, and the electric valve motor control system is disclosed and claimed in my copending application Serial No. 112,042, filed November 21, 1936, both applications being assigned to the assignee of the present application. The present application is made to protect the further invention which the applicant believes to be present in the apparatus set forth in the claims hereof over and beyond the claims set forth in the above mentioned applications.

electrical conditions;

matically shown. it will be obvious to those skilled in the art that changes and modifications may be made without departing from my invention, and I, therefore, aim in the appended claims .to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:-

1. In an electric valve translating circuit for transmitting energy between alternating current circuits of different frequencies, the combination of an electric valve means interconnecting said circuits, and an excitation circuit for controlling the conductivity of said electric valve means comprising electronic discharge means of the gaseous type for conjointly rendering said electric valve means conductive during intervals when predetermined electrical conditions of both of said alternating current circuits are satisfied.

2. In combination, an alternating current supply circuit, an alternating current load circuit, electric valve means of the gaseous type including a control member of the immersion-ignitor type interconnecting said circuits, and an excitation circuit for effecting energization of said immersion-ignitor to render said electric valve means conductive periodically in accordance with predetermined electrical conditions of said supply circuit and said load circuit comprising an electronic discharge device of the gaseous type inmay be applied to electric valve means in accordf cluding an anode, a cathode and two control members, means energized irom said supply circuit including a capacitance connected to be discharged through said immersion-ignitor and said electronic discharge device, means associated with said supply circuit and connected to one of said control members tending to render said electronic discharge device conductive in accordance with a predetermined electrical condition of said supply circuit and means associated with said load circuit and connected to the other at said control members of said electronic discharge device for conjointly rendering said electronic discharge device conductive in accordance with the combined predetermined electrical conditions of said supply circuit and said load circuit.

3. In combination, an alternating current supply circuit, an alternating current load circuit, electric valve means employing a control member of the immersion-ignitor type, and an excitation circuit for effecting energization of said immersion-ignitor member to render said electric valve means conductive periodically during predetermined portions of the cycle of alternating potential of said supply circuit and in accordance with predetermined portions of the cycle of alternating potential of said load circuit comprising an elec-- tronic discharge device of the gaseous type including an anode, a cathode and two control members, means associated with said load circuit and connected to one or said control members of said electronic discharge device tending to render said device conductive during predetermined portions of the cycle of alternating potential of said load circuit and means associated with the supply circuit and connected to the other of said control members of said electric discharge device for rendering said device conductive during predetermined portions of the cycle of alternating potential of said supply .circuit.

4. In combination, an alternating current supply circuit, an alternating current load circuit, electric valve means interconnecting said circuits, and an excitation circuit for conj ointly controlling the conductivity of said electric valve means in accordance with predetermined electrical conditions of said supply circuit and said load circuit comprising two serially-connected electronic discharge devices, and means associated with said supply circuit and said load circuit for rendering conductive simultaneously said serially-connected discharge devices in accordance with predetermined electrical conditions of said supply circuit and said load circuit.

5. In combination, an alternating current supply circuit, an alternating current load circuit, electric valve means including an anode, a cathode and a control member of the immersion-ignitor type interconnecting said circuits, an excitation circuit energized in response to the voltage appearing across said anode and said cathode of said electric valve means for controlling the conductivity 0! said electric valve means comprising two serially-connected electronic discharge devices connected between said anode and said immersion-ignitor, means for rendering one of said electronic discharge devices conductive during predetermined portions of the cycle of alternating potential of said load circuit and means associated with said supply circuit for rendering the other of said electronic discharge devices conductive during predetermined portions oi the cycle or alternating potential of said supply circuit.

6. An electric valve converting system comprising a source of alternating current, electric translating apparatus including a plurality of phase windings, a group or electric valves interconnecting said phase windings and said source, a connection between said phase windings and said source, and electronic discharge means for controlling the conductivity of said valves conjointly in accordance with predetermined electrical conditions of said source and said phase windings.

7. An electric valve converting system for transmitting energy between alternating current circuits or different frequencies comprising electric translating apparatus including a plurality of phase windings, a group of electric valves interconnecting said phase windings and one of said circuits, a connection between said phase windings and said one of said circuits, a plurality of rent circuits of different frequencies, electric translating apparatus interposed between said circuits comprising a plurality of phase windings for transmitting energy therebetween and a plurality of electric valve means interposed between said phase windings and one of said alternating current circuits for efiecting sequential energization oi. said phase windings, a plurality of electronic discharge means each associated with a different one of said electric valve means and each including a pair of control members, and means for impressing on one of said control members of each 01 said electronic discharge devices a voltage which varies in accordance with a controlling influence derived from one of said alternating current circuits and for impressing on the other of said control members of each of said electronic discharge devices a potential which varies in accordance with a controlling influence derived from the other of said alternating current circuits to control the conductivity of the associated electric valve means conjointly in accordance with said controlling influences.

9. In combination, an alternating current supply circuit, an alternating'current load circuit, electric valve means interconnecting said circuits for transmitting energy therebetween and having a control member, and an excitation circuit for energizing said control member to control the conductivity of said electric valve means conjointly in accordance with a predetermined electrical condition of said supply circuit and in accordance with a predetermined electrical condition of said load circuit comprising electronic discharge means including a plurality of control members, means for impressing on one of said control members a voltage variable in accordance with said electrical condition of said supply circuit and means for impressing on another of said control members a voltage variable in accordance with said electrical condition of said load circuit.

- ERNST F. W. ALEXANDERSON. 

